FIELD OF THE INVENTION
A method of testing of semiconductor chips involves the use of probes which contact pertinent areas, generally metallic pads, on the chip and then pass a signal through the chip to determine performance characteristics and the like. This probe test takes place prior to wire bonding to these metallic pads. Existing probing techniques place probe marks in the same area in which the interconnection interface must located. These probe marks amount to an actual displacement of a portion of the pad in the form of a void or cavity at the initial location of probe impact followed by a hill of the pad material which has been displaced from the void or cavity. This type of probe contact is required because there is generally an oxide (in the case of an aluminum pad) on the pad surface which must be broken through to make good electrical connection.
As bond pads decrease in size to accommodate the continued miniaturization of semiconductor devices, especially in conjunction with ultrafine pitch bonding of 75 .mu.m and small pad pitches, the diameters of the ends of the probe needles used for probe testing are approaching the diameters of the ball bonds themselves which will later be made to the same pads as well as the pads themselves. It follows that probe testing of the future, if conducted in the same manner as in the past, will create potential bonding failures due to the displaced pad metal (voiding) under the interconnect interface or ball bond since the amount of pad metal moved now becomes a substantial portion of the total pad metal. The displacement of the pad metal can result in non-uniform connection between the pad metal and the interconnect interface. This non-uniform connection can lead to poor reliability over the life of the packaged unit in that the connection can more readily come apart in time or that an undesirable resistance characteristic is present.